1. Field of the Invention
The present invention relates to a patterned media and a method of manufacturing the same, and a magnetic recording apparatus provided with the patterned media.
2. Description of the Related Art
In recent years, a problem that improvement in track density in magnetic recording media installed in hard disk drives (HDD) is prevented because of interference between adjacent tracks has become obvious. In particular, to reduce a fringing effect of magnetic fields from a magnetic head has become an important technical problem.
With respect to such a problem, a discrete track recording type patterned media (DTR media) in which recording tracks are physically separated has been proposed. In the DTR media, because a side-erase phenomenon that information on adjacent tracks is erased at the time of recording and a side-read phenomenon that information on adjacent tracks is read out at the time of reproducing can be reduced, it is possible to increase the track density. Accordingly, the DTR media have been expected as magnetic recording media which can provide a high recording density.
Conventionally, a DTR media is manufactured by a method comprising: etching a ferromagnetic layer deposited on a substrate to form magnetic patterns such as recording tracks or the like, filling a nonmagnetic material such as SiO2 in recesses between the magnetic patterns by bias sputtering, and etching-back the nonmagnetic material to flatten the surface of the media (see IEEE Trans. Magn., Vol. 40, pp. 2510 (2004)).
The reason of using such a method is because it has been believed that the flying characteristics of a magnetic head are made unstable when the depths of recesses on the surface thereof are too great. Thus, the problem that the flying characteristics of the head are made unstable is solved by flattening the surface by filling a nonmagnetic material in the recesses between the magnetic patterns.
However, when the surface of the DTR media is flattened, a flying height of the magnetic head is made greater, which brings about the problem that a signal-to-noise ratio (SNR) of burst signals is lowered. Further, in the case where the surface of the DTR media is flat, there is also a problem that, at the time of a crash of the magnetic head against the surface of the media (head crash), the lubricant is easily lost from the surface of the media and the media is damaged, which makes the life of the drive short.